There is used a KVM (K: Keyboard, V: Video, M: Mouse) switch that is connected to a plurality of computers and a set of consoles, and selects a computer which inputs and outputs signals from/to the set of consoles. The set of consoles includes input and output devices, such as a keyboard, a mouse and a monitor. As types of the KVM switch, there are a single-type KVM switch which is connected to a set of consoles and a multi-type KVM switch which is connected to a plurality of sets of consoles. For example, Japanese Laid-open Patent Publication No. 2011-107914 discloses a KVM switch which is connected to a plurality of sets of consoles, and performs switching between the respective sets of consoles and a plurality of computers.